1. Technical Field
This invention relates generally to lenses such as contact lenses, and more particularly to a new and improved apparatus and methodology for disinfecting such lenses.
2. Background Information
Contact lens disinfection involves deactivation or killing of microorganims on lenses and results in improved eye comfort and safety. Probably the oldest method of doing this is called heat disinfection, and it proceeds by heating the lenses while they are submerged in a suitable liquid within a lens case. In comparison, chemical disinfection involves bathing the lenses in low dosages of chemicals that are toxic to the microorganisms but not to the eye, and a typical oxidative disinfectant system utilizes a peroxide, such as hydrogen peroxide, to attack the unwanted microorganisms. In each case, disinfection is usually left to the contact lens owner to perform, most often at home between periods of lens usage and frequently as often as once or twice each day.
Depending on which technique is used, disinfection may take from approximately twenty minutes to four hours to accomplish. In addition, it often requires attention to various procedural details of little interest to many contact lens owners. Furthermore, the required lens cases, chemicals, and other disinfection paraphernalia often seem to complicate the process all the more, and lens owners often, simply forgo a recommended lens disinfecting regimen to avoid the inconvenience. Consequently, it is desirable to have a new and improved lens disinfecting apparatus that overcomes these concerns--one enabling quick and convenient disinfecting with little skill and effort.
One method cf reducing disinfecting time is described in U.S. Pat. No. 4,202,740 to Stoner. The Stoner patent describes an apparatus and method for disinfecting objects with an electrolytic process that takes three to five minutes. The lenses are held between a pair of electrically conductive members, and these members are then submerged in an electrolyte solution within an electrolytic cell. Then, a six to ten volt alternating current is impressed across a pair of electrodes in the cell, and this causes electrolytic disinfection of the lenses.
Thus, the Stoner patent discloses an electrolytic technique that decreases disinfecting time significantly. However, the particular design employed needs improvement. The time involved is still more than desirable for quick, on-the-spot disinfecting, and the structure employed is rather complex and unwieldy for use by the average contact lens owner.
Canadian Patent No. 1 156 420 to Tomei Sangyo Kabushikik Kaisha (inventors Tanaka, et al.) describes another method and apparatus for electrolytic disinfecting. The apparatus described in the Tomei patent includes a lens case that is similar in many respects to a conventional lens carrying case. However, the lens case includes a pair of electrodes at the bottom of each of two separate lens wells, and it is shaped and dimensioned to fit into an opening in a separate power supply unit.
When the carrying case is inserted into the opening, the electrodes become electrically connected to control circuitry within the power supply unit. By activating a power switch to turn on the power supply and a starter switch to begin the disinfecting cycle, a thirty second current pulse is passed through the electrodes, and this electrolyzes a physiologic saline solution in the lens wells to generate hypochlorite ions that disinfect the lenses. If desired, the cycle is repeated. Then, the carrying case is removed from the power supply unit, and the lenses removed from the carrying case for use.
The apparatus described in the Tomei patent presents certain concerns. For one, the power at the electrodes imposes a significant waiting period on the lens owner, and it would be advantageous to provide an apparatus that even further reduces the time required. In addition, the apparatus employs two units, both a lens case and a power supply, and sometimes one of the units becomes lost or is left behind. Also, the step of inserting the lens case into the power supply unit increases disinfecting time even more and involves more attention and manual dexterity than many lens owners would prefer. Thus, it would be advantageous to have an apparatus that overcomes these concerns as well.
The system of the Tomei patent has two wells, and each one must be opened to replenish the solution within or gain access to the lenses. Besides the time involved, the type of cover employed over each of the lens wells tends to wipe across the lip of the well when removed, and this often transfers contaminants to the interior. Although some existing lens cases have hinged covers with snap-on locking arrangements, these may be relatively difficult to operate so that a wiping action results between the cover and lip that transfers contaminants also. Furthermore, the relatively small electrodes within the lens wells limit electrolysis by virtue of their small surface area, and they tend to concentrate electrolysis at a central bottom region of the well around the anode. This is somewhat inefficient. Also, the bubbles produced as the solution is electrolyzed tend to lift the lenses to the upper surface of the solution where the disinfecting action is less effective.
Consequently, it would be advantageous to have a new apparatus for disinfecting lenses that overcomes these and other concerns to be described--one that is conveniently carried and operated to provide quick, portable, and reliable on-the-spot lens disinfecting.